Spiral conveyer belt



March 22, 1932. F N. WOODMAN SPIRAL CONVEYER BELT Filed Dec. 12, 1928 I 4 $02618 fMaihvou A NW T Patented Mar. 22, 1932 UNITED STATES PATENT OFFICE FRANCIS N. WOODMAN, OF CLINTON, MASSACHUSETTS, ASSIGNOR '10 WICKWIRE SPENCER STEEL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE SPIRAL'CONVEYER BELT 7 Application filed. December 12, 1928. Serial 80,325,601.

This application is a continuation in part of my prior application Serial No. 271,323

and the invention relates to a conveyer belt" formed of interlaced spiral wire members.

When such belts or conveyers are operated under excessive tension, and particularly when exposed at the same time to relatively high temperatures, there is a marked tendency to stretch the conveyer and at the same time to reduce the width.

It is one object of my invention to provide means for maintaining such a conveyer belt at substantially full width, even under adverse operating conditions.

To the attainment of this object in the preferred form, I provide compression-resisting elements in and between certain of the spiral wire members, so disposed relative thereto as to effectually prevent substantial contraction of the conveyer transversely or widthwise thereof. If the belt is thus held from transverse shrinkage, lengthwise stretching of the belt is also substantially eliminated.

A further object of the invention is to pro vide a conveyer belt in which the spiral members are formed of a highly heat-resistant alloy. by which provision the utility of the belt is greatly increased and its field of application extended, as will be hereinafter explained.

Preferred forms of the invention are shown in he drawings in which Fig. 1 is a plan view of a portion of a conve er belt embodying mv improvements:

Fig. 2 is an enlarged sectional end elevation, taken along the line 2--2 of Fig. 1:

Fig. 3 is an enlarged detail end view. looking in the direction of the arrow 3 in Fig, 1';

Fig. 4 is a view similar to Fig. 1, but showing a modified construction; and

Fig. 5 is a diagrammatic view illustrating a novel use of my improved belt.

Referring particularly to Figs. 1 to 3, my improved belt comprises aseries of wire members 10 which are wound in spiral form and are interlaced with adjacent spiral members as shown. After the spiral members are thus interlaced, the thickness of the belt may be reduced by passing the belt between pressure rolls eifective to more'or less flatten the round spirals, as indicated in Fig. 3.

In order to prevent widthwise contraction or shrinkage of thebelt, I placecshrinkage resistlng members or rods 12 in and between certain adjacent spiral wires 10,'as indicated in Figs. 1 and 2. The 'selvage ends of successive pairs of said adacent wires are then bent and looped together, as shown in Figs. 1 and 3, thus providing a smoother edge for the belt and also presenting a barrier at each edge of the belt, effective to prevent longitudinal displacement of the rods 12.

It will be understood that the rods 12 are inserted at selected intervals along the-belt,

varying with the conditions of operation. In some casesthe rods may be quite close together, whereas in other cases a rod once in six or eight or even ten inches may be sufiicient.

When excessive tension is placed on a wire conveyer belt, there is a tendency to elongate I spiral wires 10 to abut the ends ofthe rods 12, this is not indispensable, as the advantage described may be to a large extent attained in the construction shown in Fig.4, in which the bent ends of the spiral members do not abut the rods 12. It is foundjthat the heavy tension on the spiral members when in use causes them to bite into the rods-12 and form close frictional contact therewith, so that slipping of the spiral coils along the rods is efiectively prevented, even without the abutting bent ends.

In either form of the construction. the rods 12 also fit closely into the curves of-the spiral der strain. Such strain causes the spiral coils to bend more sharply about each other, elongating the belt, but in my construction this shar bending is largely avoided by the close fit o the rods between the coils.

It has heretofore been considered impossible, or at least impractical, to use spiral wire conveyer belts in furnaces or in other places where they are exposed to high temperatures. Whenexposed to such high tem peratures, the longitudinal stretching and transverse shrinkage of the belts is greatly increased and it was found impossible to maintain a belt in anything like its original dimensions. I find, however, that by. constructing a belt out of wire drawn from a special high temperature heat-resisting alloy and particularly by utilizing my shrinkageresisting cross bars in a belt formed from such wire, that a conveyer belt may be produced which may be effectively used for conveying articles through an annealing or heattreating furnace or for other purposes where hi h temperatures are encountered.

hile I do not wish to be limited to the use of a specific alloy, the following composition has been found suitable for belts exposed to a range of temperature up to 1600 F.

Carbon .16 to 24% Chromium 17 to 18% Nickel to 26% Silicon"; 2 to 3% Iron 55.84 to 52.76%

Such a special alloy, heat-resisting belt possesses many advantages over the conveyer devices now in use for high temperature work, and these advantages are increased by using my shrinkage-resisting rods in such a belt.

My improved belt has a very low thermal capacity and consequently lends itself to heat economy. The belt has a substantially continuous unbroken smooth surface and is substantially free from vibration, as compared with belts formed of linked plates and other similar structures. This is of particular importance in enameling jewelry in silversmith work, and in any other operation where vibration may disturb the relative position of the parts or elements thereof.

My improved belt is easily spliced and is continuous after splicing, there being no projection or difference in thickness at the point where the splice is made. The belt does not warp or crack as has been the case with sheet metal link belts and the natural flexibility of the belt permits it to run smoothly over relatively small rollers or pulleys if necesdesired width or length, and the two sides of the belt are commonly identical, so that the belt may be reversed and the wear on the belt may thus be evenly distributed.

vention are attained by a combination of these two features and by such combination a belt is produced which is available for use under conditions heretofore considered impossible for wire belts.

In Fig. 5, I have indicated my improved belt B in use for conveying material or articles of manufacture through an annealing enameling or heat-treating furnace F, in which combination the advantages enumerated may be fully attained.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is 1. A wire conveyer belt effective to transport articles or products of substantial weight and comprising a series of interlaced spiral wire members, a series of cross rods extending transversely of said belt, each of said rods being positioned in and between the spaced turns of two adjacent interlaced spiral wire members, whereby substantial change in width of said belt is effectively prevented, and means for holding the rods and wires against relative lateral displacement, in either direction transversely of the belt.

2. A wire conveyer belt effective to transport articles or products of substantial weight and comprising a series of interlaced spiral wire members, and a plurality of com ression-resisting cross rods inserted in an between the coils of certain of said spiral wire members and relatively closely spaced longitudinally of said conveyer belt, whereby substantial transverse shrinkage of said belt is effectively prevented, said cross rods being retained against endwise movement transversely of said conveyer belt by abutting edge portions of said belt.

3. A wire conveyer belt effective to transport articles or products of substantial weight and comprising a series of interlaced spiral wire members bent and looped together in successive pairs at the edges of said belt, and shrinkage-resisting cross rods loosely inserted in and between the overlapping portions of certain of said joined pairs of spiral wire members and engaging at their ends with the bent and looped ends of said spiral wire members, whereby displacement of said cross rods and substantial transverse contraction ofsaid conveyer belt is efiectively prevented.

' 4. A wire conveyer belt eflective to transport articles or products of substantial weight during heat treatment thereof at high temperatures, said belt comprising a series of interlaced spiral wiremembers formed of -a highly heat resistant metal, and a series of cross rods extending transversely of said belt and held from endwise displacement-therein,

each of said rods being pbsitioned in and be-- tween the turns of two adjacent interlaced spiral wire members, and means for holding the rods and wires a ainst relative displacement in either direction, said cross rods frictionally engagin the coils of said spiral wire members, where y movement of the spiral coils axially of said rods is prevented when said belt is under load tension. o 5. A wire conveyer belt efiective to transport articles or products of substantial weight during heat treatment thereof at'high temperatures, said belt comprising a series of interlaced spiral wire members formed of as highly heat resistant metal, said members being bent and looped together in successive pairs at the edges of said belt, and shrinkageresisting cross rods loosely inserted in and between the overlapping coils of certain of said joined pairs of spiral members, whereby substantial transverse contraction of said conveyer is eflectively prevented when underloa d tension, said rods being held from endwise displacement transversely of said belt by abutting the bent and looped ends of said spiral wire members.

- In testimony whereof I have hereuntoaffixedmy signature.

' FRANCIS N. WOODMAN. 

